Thread element and process and apparatus for making it



May 18, 1937- F. E. BARTELL THREAD ELEMENT AND PROCESS AND APPARATUS FOR MAKING IT Filed Jan. 20, 1936 z M Q m MM T. N w m h l d M Q\ M il \1 .Q. 0 J 5 J k h v 3 F M J U wihfiibtiuxmwmk If M5 M Patented May is, 1937 UNITED STATES PATENT OFFICE Floyd E. Bartell. Ann Arbor, Mich anlgnor to G. E. Wilder, William A. Defnct, Sherwood Field, J.

Hugo Smith,

Frank MaoKenzie,

Yellott F. Hardcastle. D. Kenneth Laub, Duncan J. McNabb, and Stanley V. Laub', all of Detroit, Mich.

Application January 20, 1936, Serial No. 59,831

6 Claims.

The invention relates generally to textiles and it has particular relation to a threadlike element and a process and apparatus for manufacturing it. It also constitutes a continuation in part of the subject matter embodied in my co-pending alaggication Serial No. 36,796, filed August 19.

One object of the invention is to provide an improved thread that can be manufactured inexpensively.

Another object of the invention is to provide an improved thread that is substantially imperforate and which is highly resistant to the passage of water therethrough.

Another object of the invention is to provide an improved thread of the above character that may be readily made of diflerent denier.

Another object of the invention is to provide an improved threadlike element, which may be used as a bristle for brushes or the like.

Another object of the invention is to provide a process of manufacturing thread of the above described character that will enable production of a uniform product and also enable production 5. of threads varying in denier.

55 like, are provided on supply spools ll rotatably Another object of the invention is to provide an apparatus for manufacturing thread of the above identified character in a simple and inexpensive manner.

Other objects of the invention will become apparent from the following specification, the

drawing relating thereto and from the claims.

hereinafter set forth.

For a better understanding of the invention, reference may be had to the drawing wherein:

Fig. 1 is a vertical and longitudinal cross section of an apparatus employed in manufacturing thread or the like according to one form of the invention;

Fig. 2 is a cross sectional view on a larger scale taken substantially along line 22 of Fig. 1;

Fig. 3 is a cross sectional view on a larger scale taken substantially along line 3-3 of Fig. l;

Fig. 4 is a cross sectional view on a larger scale taken substantially along line 4-4 of Fig. 3 and illustrating generally the character of the several filaments used in manufacturing the thread; and

Fig. 5 is a fragmentary cross-sectional view illustrating a form of apparatus that may be employed to produce a flattened thread.

According to one form of the invention, a plurality of filaments ill of cellulosic material such as cellulosic acetate, cellulosic nitrate, or the mounted on a pin I! supported by brackets i3. Each of the filaments, as best shown by Fig. 4, comprises a number of loose minute filaments i4 and it will be understood that the collected minute filaments constitute a commercial thread that is now produced from cellulosic material. The filaments l lead througha suitable guide bracket l provided with a guide aperture it for each individual filament i0, and then the filaments pass through a tank or vat ll containing a treating solution i8 capable of gelatinizing or softening the cellulosic material, a pivoted drop arm i9 is provided with a guide notch 20 for collecting and keeping the filaments l0 immersed in the solution I! during their passage through the tank or vat II.

The treating solution i8 may be termed a gelatinizing agent for cellulose esters, and. is composed preferably of ethyl acetate, acetone, or other so-called solvent for cellulose esters. While cellulose probably does not form a true solution in any of its ordinary solvents, it may be dispersed colloidally by such solvents. In limited amounts of such solvents, swelling of the esters occurs and a gel is formed." The exact nature of the gel formation is not fully understood, but it is believed that the solid or semisolid material portion of the gel is converted to the colloid state, in which state it possesses a very great specific surface area; that is, large surface area per unit volume of material; hence a great interfacial energy which effects in a product, high cohesional and high adhesional properties. Ethyl acetate is an excellent, fast evaporating, gelatinizing agent for cellulose acetate. Acetone is likewise a fast evaporating solvent, peptizing or gelatinizing agent for certain cellulose esters, resin and many other organic compounds A solution of'alcohol and ether (as 75% alcohol, 25% ether) is a gelatinizing agent for cellulose nitrate.

The time the filamehts are allowed; to remain in the solution I8 is of importance. Ifallowed to remain too long, the cellulosic material comprise ing the filaments-may be dissolved and pass into the solution, in which event the filaments would.

lose their identity as such. It is desired to retainthe filaments in the solution only for a time sufllclent to gelatinize and soften the outer surface portion of each minute filament, while leaving a central core thereof substantially unaffected, and ordinarily all minute filaments will be acted upon by the solution owing to the fact that the latter is quite volatile and quickly: penetratesin and between.1filaments. It may; be

that the minute filaments H would be grouped closely enough so as to prevent the solution reaching each minute filament at all points, but it seems that all or substantially all of the outer surface of each minute filament II can be acted upon by the solution. It is also possible that the action may vary to some extent as the solution will touch the outer minute filaments perhaps an infinitesimal instant before reaching the inner minute filaments. The desirable result is that all minute filaments will have their outer surface portions gelatinized so that subsequently all of the collected filaments may become bonded in an integral mass, but it will be appreciated that some variation might be obtained. For example, if it be assumed that one of the inner minute filaments is not acted upon by the solvent, the outer group of minute filaments still would integrally bond together around the unaffected filament. This is mentioned for the reason that it is difiicult to determine that any one inner minute filament or part thereof is unaffected. Experiments seem to indicate the solution quickly penetrates between all minute filaments and gelatinizes the outer surface portion of each.

After leaving the solution, the collected filaments pass through a rotary tube 22 mounted in bearings 23. The tube is provided with a bevel gear 24 that meshes with a gear 25 in turn driven by a shaft 26. The latter at its lower end has three pulleys 21, 28 and 29, the latter pulley being engaged by a belt 30 that is trained about a pulley 3| on the shaft of a motor 32. the tube has a flared mouth to facilitate passage of the filaments thereinto and to avoid an undesirable scraping action on the filaments, and the left end of the tube has a stopper 33 composed of cork, rubber or other suitable material. The stopper has an axial opening 34 through which the filaments pass and it seems preferable that this opening be slightly eccentric to the axis of the tube, although it may be concentric. It is of such size, however, that rotation of the stopper with the tube causes an appreciable twisting or frictional force to be applied to the outer surface of the grouped filaments passing therethrough so as to compact the filaments closely together, while at the same time cause the outer surface of the group to be rendered smooth, substantially round and imperforate. Moreover, the compacting of the filaments substantially removes any voids between the minute filaments, so as to leave a substantially solid, round, imperforate thread element 35 having a'smooth outer surface. After the filaments leave the solution, with the outer surface portions only of the minute filaments gelatinized, they will become bonded together through surface union of adjacent filaments but the gelatinized condition of the outer surface portions of the minute filaments is retained at least partially until the group enters the stopper so as to permit compacting of the filaments, eliminating voids therein, rounding of the thread and providing a smooth outer surface therefor. Evaporation of the solvent from the filaments begins as soon as they leave the solution, but it is intended that the evaporation will not besuificient to prevent obtaining the particular results mentioned through action of the rotary stopper and that after leaving the stopper, the form and condition of the thread then may be retained.

It may be mentioned that some twisting of the filaments by the stopper seems to occur between The right end of I the stopper and arm fl and even beyond the latter and accordingly from the time the grouped filaments leave the solution, they are subjected'to some forces tending to compact'them and to bring them into an integral union as the gelatinized surfaces of the filaments are drawn together. Evaporation of the solvent will continue, of course, but in any event the grouped filaments are still in a formative condition when they pass through the stopper so as to permit some change in the united gelatinized surfaces of the filaments to obtain the desired finished thread condition. It may be added that the apparatus may be so arranged that the filaments do not touch the tube if this is desired.

It appears that no permanent twisting of filaments is obtained in the finished thread even though they appear to be in a twisted condition between the stopper and the solution. Possibly there may be some fracturing of filaments, and reunion thereof through the gelatinized material adjacent the fracture, or perhaps there may be a release of the twist after the thread leaves the stopper. In any event, frictional twisting forces are applied, some twisting occurs between the stopper and solution at least, and the finished thread after it leaves the stopper appears substantially to have no twist.

The finished thread is wound upon a spool 38 driven through gears 39 and 40, a reduction gearing 4|, a pulley 42 and a belt 43 engaging the pulley and also the pulley 28. The distance between the spool and stopper maybe such as to allow complete evaporation of any solvent retained by the thread or a fan 44 for example may be placed adjacent the stopper to accentuate complete evaporation. As shown, the fan is driven by means of a pulley l5 and a belt 46 engaging the latter and the pulley 21. While the results have been satisfactory without a fan, it is reasonable that the fan would act to obtain a quick evaporation of any solvent in the thread as the latter leaves the stopper and it seems desirable to have the solvent evaporate quickly after the thread is finally formed by the stopper.

It is to be understood that the tube, stopper and fan are rotated preferably at a high rate of speed while the thread is pulled therethrough by the spool 38 at a relatively slow rate of speed. In this connection it is to be noted that the filaments are under some tension as they move through the stopper and this seems desirable.

It appears that the longitudinal rigidity of the thread is materially increased and this may be caused by hardening and rendering more dense the outer surface portions of the individual filaments. A possible explanation of this result may also reside in the fact that the filaments are stretched through the tension and also the twisting action, resulting in a definite molecular orientation or crystallization of the material with the crystals extending lengthwise of the thread so that the filaments are set in this condition as the treating solution evaporates. The outer portions of the filaments which had been gelatinized or softened, upon drying become relatively hard, firm and flexible.

Various denier threads may be manufactured by increasing the number or size of the filaments III that are employed. The product may be woven into cloth, curtains and the like, and desirable sizes thereof may be used for bristles in brushes. A great many uses of the product will occur to those interested in this art. The imperforate surface of the product, its solidity and freedom from voids, its water resistant characteristics due to the material and its freedom from voids and perforations, and its integral nature due to integral bonding of the filaments, render it highly useful for manufacturing water resistant fabric, water. resistant brushes and the like.

Figure 5 relates to the same apparatus but additionally provides a pair of rollers 48 and 49 between which the threadpasses after leaving the stopper. It will be understood that the apparatus will be adjusted if necessary to insure that the thread will still be in a formative condition sufficient to permit the rollers to flatten it and then to cause the flattened thread to retain its new form. Various contours of rollers might be used to vary the form of thread obtained in this manner.

As many changes may be made in the above product and many apparently widely different means may be employed for carrying out the method of making the same, itis intended that all matter contained in the above description or shown in the accompanying drawing, shall be interpreted as illustrative and not in a, limiting sense.

What I claim is:

1. The method of manufacturing a threadlike element which comprises treating a plurality of filaments of cellulose esters with a gelatinizing solution to soften the filaments, assembling the filaments, applying rotary sliding forces tending to twist the filaments while maintaining them under tension, and then causing evaporation of the solution.

2. The method of manufacturing a threadlike element which comprises passing a plurality of filaments'of cellulose esters through a gelatinizing solution to soften and gelate only the outer surface portions of the filaments, assembling the filaments, applying rotary sliding forces-tending to twist the filaments, and then causing the solution to evaporate.

3. The method of manufacturing a threadiike element which comprises passing a plurality of filaments of cellulose esters through a gelatinizing solution to soften and gelate only the outer surface portions of the filaments, assembling the filaments and applying rotary sliding forces tending to twist them while'maintaining the filaments under tension, and then causing the solution to evaporate.

4. The method of manufacturing a threadlike element which comprises passing a plurality of filaments of cellulose esters through a gelatinizing solution to soften and gelate only the outer surface portions of the filaments, assembling the filaments and applying rotary sliding forces. tending to twist them while maintaining them under tension, and then causing the solution to evaporate while maintaining the filaments under tension.

5. The method of manufacturing a threadlike element which comprises passing a plurality of cellulosic filaments through a solvent to gelatinize the outer surface portions of the filaments, bringing the filamentstogether and applying rotary frictional forces to the assembly to compact the I filaments and provide a single element having a smooth, substantially imperforate outer surface and simultaneously bonding the filaments together through union of the gelatinized surface, and then evaporating the solvent.

6. The method of manufacturing a threadlike element which comprises subjecting a plurality of cellulosic filaments to the action of a solvent so as to gelatinize the outer surface portions of the filaments, assembling the filaments and applying rotary frictional forces to the outer surface of the assembly to compact the filaments and provide a single substantially imperforate element having a smooth outer surface and to cause the gelatinized surfaces to unite-and bond the filaments together, and then evaporating the solvent.

FLOYD E. BARTELL. 

